SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a53b935620f67be7bdef587440bd9319b11a38f400dc14733aafb014e0e329a' 
  AND token = 'XI+hgBhWBlBy/qehANkxPYAUioCEkAa6oR18mteAOOg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}